Process of recovering copper from its ores



c. J. A. DALZIEL. PROCESS OF RECOVERING COPPER FROM ITS ORES.

APPLICATION FILED SEPT 24, 1918.

Patented June 1, 1920.

M. W m a M T if.

CHARLES JOSEPH ALBERT DALZIEL, LONDON, ENGLAND.

PROCESS OF RECOVERING COPPER FROM ITS ORES.

Specification of Letters Patent. I Patented J 11116 1, 1920,

Application filed September 24, 1918. Serial No. 255,469.

To all whom it may concern:

Be it known that 1, Cinemas JOSEPH AL- BERT DALZIEL, a subject of the King of Great Britain, whose residence is in London, Eng land, have inventedcertain new and useful Improvements in Processes. of Recovering Copper from Its Ores, of which the following is a specification.

. According to this invention copper is extracted and precipitated directly from a pulped copper ore by a single continuous operationwithout filtration. Apcording to this invention the copper ore is supplied to one or more preparatory vessels through a chute or chutes which is provided with suitable means'for controlling the supply of ore to the vessel and a dilute acid solution is supplied to the preparatory vessel through a pipe or conduit provided with suitable means forregulating the supply of the solution to said vessel.

-'The preparatory vessels are identical in construction and equipment. Either one or both of the preparatory vessels may be used and the continuous operation of the process need not be affected by the failure for any reason. of-either of said vessels as both being identical in construction either one can carry on the process independently of the other if necessary.

The solution and the finely crushed copper ore together form a bulk of acid pulp containing copper ore in a liquid. p The pulp is agitated and aerated in the prepara tory vessel or vessels by compressed air in jectedintothe same for purpose of keeping the ore in suspension in the solution. The ore thus treated is led to the first of a series of electrolytic vessel's where it is agitated and aerated by compressed air, and an electric current is passed from an insoluble anode through thepulp to a cathode upon which the copper is deposited by the action of the electric current.

The pulp is then led to the second of the series of electrolytic vessels similarly equipped with electrodes and with means for agitating and aerating'the p'ulpand is then led from the second to the third electrolytic vessel in the series and is then led through the remainder of the series of electrolytic vessels which series may consist of any number of vessels or cells equipped with elec- I number of electrolytic vessels will depend upon the length of time required to deposit the copper contained in the pulp upon the cathodes. I

As the pulp is led from the preparatory vessel to the electrolytic vessels or cells, fresh ore and acid solution is added to the preparatory vessel toprovide a continuous supply of acid pulp to take the place of the pulp which is drawn off from the last electrolytic vessels and which hasbecome depleted of its copper content by electrolysis.

By regulating the flow of ore and of solution into the-preparatory vessels and correspondingly regulating the flow of depleted pulp from the last of the series of electrolytic vessels a continuous supply of freshly charged pulp of approximately uniform strength in copper is delivered to the electrolytic vessels, thus enabling a uniform strength of electric current to be used and insuring a continuous cycle of operations which need only be interrupted for the purpose of carrying out repairs or replacements upon the character of the particular ore under treatment. Thus with sulfid ores it is preferable to roast the ore at the commencement of the operation, thereby converting a large part of the copper content of the ore into sulfate, during which operation a part of, the copper will ordinarily be converted into oXid.

The process may be conyeniently carried out in an apparatus of the kind illustrated in the accompanying drawings in which:

50 ploy an amount of sulfuric acid capable of Figure 1 is a diagrammatic view of a suitable apparatus for practising the process.

Fig. 2 shows on a larger scale a vertical section of one of the electrolytic vats or cells.

I Ore is fed into the preparatory vessels 1 and l through chutes 2 in regulated quan- V tities'. Valves or gates 2, as indicated, reg

ulatc the flow of the ore. An acid leach solution is fed to each preparatory vesselfroin a tank 3 through pipesl each provided with a valve 4 the amount of solution fed being such as to produce a thin fiowable pulp in the preparatory vessels. I prefer to introduce the ore and the solution simultaneously so that there will be more or less agitation produced as they enter thevessels.

In order to produce acomplete suspension of the ore in the preparatory vessels a blast of air is introduced through a per forate'd pipe 5 at the bottom of each vessel. The air thus introduced produces aeration and agitation of the pulp so that a more or less homogeneous flowable pulp is produced and the oreparticles are held at all times in suspension. The air thus introduced also serves'to some extent'to aid solution of the copper contained in the-suspended ore.

"cell through suitableoverflow connections 11 The pulp being thus thoroughly aerated and agitated isallowed to flow oil through 'the pipes 6 having valves a into the first of a series of electrolytic cells or vats 1 to 9,. these cells being prbvided with insolu- "ble' anodes and cathodes and with an air blastlO located at the bottomof each vessel for the purpose of maintaining the ore in I, 8, etc.,

suspension therein and for agitating and aeratlngit. The liquid flows from cell to dissolvingthe entire copper content of the ore and ,in practice'only a small quantity. of sulfuric acid is employed, since the electrolysis ofthe liquor in each of the electrolytic cells will regenerate a portion of the sulfuric acid, which portion being regenerated in a substantially nascent state reacts at once with more; of the copper contained in the ore.

In each of the cells 7, 8, etc., to 9, insoluble anodes 15 are suspended and are associated with cathodes 16.

The anodes are connected to a suitable support 17, connected to the positive wire of a suitable generator orother'source' of electricity and the cathodes are pro erly connected to' the negative wire Molthe circuit. i h

It will be observed that I do not at any to filtration, which operationis expensive not onlyin apparatus employed 'but,in the attendance required.- It also will be ob-' served that I do not, at any stage of the process, heat or boil the liquor, and the entn'epperation taking place in the apparatus illustrated is conveniently conducted at ordinary atmospheric temperature. I there-' by avoid the expense incident to heating the liquors, and to maintaining said liquor in a heated state. cells depends upon the speed of flow desired and the time required to deposit substan-; tially the entire content of copper contained in the ore.. j ;,i;;'

In practice it is advisable. after startin The number of electrolytic the operation to introduce continuously in" regulated amounts the finelyv crushed ore,

through the chutes 2and'regulated amounts of liquid from the tank 3, thereby maintain-r" ing a full supply of the ore and liquid in the preparatory vessels. overflow throughthe pipe 6 and the passage of the liquid through the pipes 11 and dis charge pipe 12 is made continuous and re-' quires little service from an attendant;

In this way, the

As the drawings indicate, I'preferabIy employ two preparatory vessels'l and 1 and the copper ore is supplied to both of these vessels, which are identical in can: Stl'lKtlOIl and equipment.

The ore is supplied thrcnlgh two chutes 2, each of which is provided with means for controllingthe supply to the vessel, and a dilute acid solu- I no tion is supplied to both vessels through pipes I or conduits 4,'ea'ch provided with suitable means .4 for regulating the supply of the solutioifrto said vessels. Either one or'both-v of the preparatory vessels may be used and the continuous operation of the process need;

of either of the preparatory vessels. Either one can carry on the process independently of the other if necessary.

I claim as my invention: l. The herein described process not be affected by the failure for any reason.

11a a i tracting copper from its ores-which consists;

in supplying to a preparatory vessel finely crushed ore and an acid solut1on,-1n such proportions as to produce a flowable pulp, U forming the said ore and solution into a flowable pulp by aeration-agitation in said vessel, passing the pulp of liquor and ore once only through a series of electrolytic cells separate from said preparatory vessel, while preventing sedimentation in said cells by introducing a blast of air at the lower 70 i stage of the operationsubject the pulped orepart of each of said cells,

only of the amount of acid which would be chemically equivalent to the copper content of the saidore, in such proportions as to form a readily flowable pulp, forming the said ore and solution into a flowable pulp solely by aeration-agitation in said vessel, passing the p'iilp of liquor andore once only through a series of electrolytic cells separate from said preparatory vessel, while preventing sedimentation in said cells, and continuously discharging the substantially barren pulp from the last of said cells.

3. The herein described process of extracting copper irom its ores which consists in supplying to a preparatory vessel, finely crushed ore and an acid solution containing a fraction only of the amount of acid which would be chemically equivalent to the cop per content of the said ore, in such proportions as to produce a flowable pulp, forming the said ore and solution into a fiowable pulp by aeration-agitation in said vessel, passing the pulp of liquor and ore once only through a series of electrolytic cells separate from said preparatory vessel, while preventing sedimentation in said cells, and con-' tinuously discharging the substantially barren pulp from the last of said cells, all of said operations being conducted at normal atmospheric temperatures.

A process of extracting copper from copper ore, which comprises pulping finely divided ore with an acid leachingsolution by aeration-agitation only, said vsolution containing a fraction only of that amount of acid which would be necessary to dissolve the entire copper content of the ore, and without filtration of said pulp,-causing the same to flow through a series of electrolytic cells until the copper content of the pulp is trolytic cells,

commercially exhausted while agitating the ore pulp as it passes through said cells, to prevent sedimentation.

5. A process of extractingcopper from sulfid ores containing copper: which coniprises first subjecting the ore to a sulfatizing roast, whereby the copper is converted principally into sulfate and ioxid, subjecting the 'finely divided roasted ore and an acid leaching solution to sufiicient agitation to produce a readily fiowable thin pulp, passing such 'pul p once only through a series of electro- "lytic cells until the copper content of the pulp is commercially exhausted and discharging the pulp from'the system.

6. The herein described process of extracting copper from its ores whichLgpnsists in supplying to a preparatory vesselfinely crushed ore and an acid! solution, in such proportions as to produce; a flowable @1111), such solution! containing materially less acid than would correspond to the amount of copper in the said ore, forfiiing the said ore and solution into a flowable pulp by aerationagitation in said vessel, passing the pulp of liquor and ore once only through a series of electrolytic cells separate from said preparatory vessel, while preventing sedimentation in said cells, and continuously discharging the substantially barren pulp from the last of said cgllll I a 7. A. process of treating oxidized copper ores which comprises continuously subjecting the said ore, in a finely divided state, in

a leaching solution, at about atmospheric temperature, to agitation produced solely (by a blast of air of sufiicient intensityand for a sufiicient length of time to produce a readilyflowable thin pulp, and continuously. passing such pulp through a series of elecwhile agitating the pulp solely by anf'air blast sufficient to prevent any such amouht of sedimentation in the cells as would substantially obstruct the same.

In testimony whereof]: have hereunto subscribed my name.

CHARLES JOSEPH ALBERT DALZIEL" 

